It is not as much the failing of the MLG (although in a few cases at a fairly low limit, some at only 1100'/min), it is
the way it fails: MLG fails -> wing(root) gets structurally damaged in the process (design) -> wing fails -> aircraft flips over -> ... a number of crashes show a similar pattern.
As far as the cause of these crashes: trained professionals establish the cause of a crash, I consider myself very lucky not having to establish cause. I just observe a pattern in
the way the MLG failed on several of these crashes.
MLG failures due to hard landings on large civilian aircraft are rare
AFAIK, but compare this pattern to f.i. the way the B777 wing gear failure at LHR (1700'/min if I remember correctly): right and left MLG collapsed, but the damage to aircraft -although substantial- was survivable to the passengers and crew (thankfully the worst injury was a broken leg). At the very least the wings were still attached to the hull (and the wing tanks remained largely intact).
But perhaps I am being a bit too outspoken on this issue (in which case I apologize); good people have died in this crash...